What is a torque hinge?

A torque hinge has the ability to retain its angle or position even when a force is applied to it.

This website will teach you about how torque hinges are used, how to calculate moment, common applications and how to search for products. You will also discover tips for selecting the correct hinge and useful tools which do the calculations and moment graphs for you.

Torque hinges are also called free-stop hinges.

The video on the right shows examples of different Sugatsune torque hinges. They add extra value and functionality to equipment in a wide number of industries. For instance, holding monitors in place at fixed angles in medical and diagnostic facilities. Or holding control panels in place in manufacturing facilities.

Without a torque hinge

Without a torque hinge, lids can slam, causing injury

With a torque hinge

With a torque hinge, the operator can move lids and flaps to place and they will reliably stay in position

As is highlighted in the example above, torque hinges can increase worker efficiency and maintenance simplicity. By holding flaps and lids in place, workers can focus on other tasks and keep their hands free. Torque hinges reduce the risk of flaps and lids slamming shut, reducing the change of injury.

3 advantages of torque hinges


Without a torque hinge, Applications need some type of stopper to hold in place

Applications need some type of stopper to hold in place

With a torque hinge, allows the lid or flap to Hold at any angle without any additional components

Torque hinges allow the lid or flap to Hold at any angle without any additional components


Without a torque hinge, multiple components and connections are required

Multiple components are required.

With a torque hinge, designs can be simplified without using lid supports

Simplified design without the need for a lid support.


Without a torque hinge, there is an increased risk of accidental closing, with the potential to cause injujry

May accidentally or unintentionally close, increasing the risk of injury.

With a
With a torque hinge, holds reliably in position wherever it is

Holds in whatever position it is set at.

How does it hold in any position?

How does it the torque hinge hold in position

Torque hinges use friction to offer resistance to motion. Moving the flap or cover causes friction, which results in its free-stop functionality. This functionality allows it to stop at any angle without any separate stopper or extra component.

Suitable Applications

Torque hinges are frequently used for equipment covers, on position adjusting sections of monitors and on lighting fixtures. These are just some of the ways in which torque hinges are used in different industries. Below are several examples of the ways in which they are frequently used in different industries to increase efficiency, convenience, ease of use and reduce the potential for injury.

Example of use of torque hinges in the medical equipment industry
Example of use in the medical industry
Example of use of torque hinges in public transportation vehicles, particularly trains and airplanes
Example of use in railroad and airline industries
Example of use of torque hinges in monitor panels of machining tools
Example of use in control panels on machining tools
Example of use of torque hinges in public transportation vehicles, particularly trains and airplanes
Example of use in food manufacturing facilities

Application examples

The following two examples are demonstrations of different applications of torque hinges. By clicking on the hinges, you can learn more about them

Example of real use example of torque hinge in a monitor

Example of torque hinge use to control rotation and tilt angle of monitor
Dual axis torque hinge HG-T30S15

Featured product: HG-T30S15 Dual Axis Torque Hinge

This dual axis torque hinge (360° rotation and tilt), featured in the product to left, allows users a high degree of positional freedom increasing the convenience of the product. This is particularly important for monitor displays with important information.

Example of torque hinge being used in coffee machine to keep it open

Example of torque hinge being used on a coffee machine to hold lid open.

Product: Caferoid, available at http://www.caferoid.jp/
From: Nihon Dennetsu Co., Ltd.

HG-TS Torque Hinge

Featured product: HG-TS Torque Hinge

This type of torque butt hinge is designed to work in a wide array of applications. This model type comes in 3 different sizes, each with its own set of torque.

Common hinge shapes

The following are five of the most common types of torque hinge shapes in Sugatsune's product lineup. These are butt hinges, bracket hinges, concealed hinges, swivel hinges and dual axis hinges. Sugatsune also has many other types of torque hinges, including lift-off torque hinges and even piano torque hinges.

Butt Hinges

Butt hinges are the most common type of hinge. These types of hinges can be observed on all kinds of different devices, including swing open cabinets and other types of flaps that open horizontally or vertically. These are also commonly used to hold maintenance compartments open.

HG-TQA One way Torque Hinge, Butt Hinge Type


HG-TS Torque Hinge, Butt Hinge Type


Bracket Hinges

Bracket hinges have an "L" shape. They have thin dimensions and are frequently placed on the sides of lids, between the lids and their enclosures. They can also be combined to create different types of motion.

HG-TA Torque Hinge, Bracket Type Torque Hinge


HG-TBSJ40 Adjustable Torque Hinge, Bracket Type Torque Hinge


Concealed Hinges

Concealed hinges are installed on the inside of flaps and machines. These create a clean appearance, improving the design and reducing protrusions.

HG-TUWA Torque Hinge, Concealed Type Torque Hinge


HG-TBSJ40 Adjustable Torque Hinge, Bracket Type Torque Hinge
Inner appearance

Application Example

HG-TBSJ40 Adjustable Torque Hinge, Bracket Type Torque Hinge
Outer appearance

Application Example

Swivel Hinges

Swivel hinges can rotate. These are often used in order to hold panels and monitors in place, especially in areas with vibration. Frequently used on control panels to control position even while buttons are being pressed while still retaining the ability to rotate.

HG-S Swivel Torque Hinge, Swivel Type Torque Hinge


HG-S Swivel Torque Hinge, Swivel Type Torque Hinge


Dual Axis Hinges

Dual axis hinges have two different axes where torque is incorporated. This allows for more complex types of movements and designs. For instance, the HG-TMH model has two separate strengths of torque on its sides. This allows for it to be opened and closed in a predictable manner. The HG-T70S30 allows for both swivel and tilt positional adjustment in a single component.

HG-TMH Dual Axis Torque Hinge, Dual Axis Type Torque Hinge


HG-T70S30 Dual Axis Torque Hinge, Dual Axis Type Torque Hinge


Torque hinge strength variation

Depending on the type, format and internal mechanisms, there can be large variations in torque strength. Further, all torque hinges have a certain amount of variability. All torque hinges operate within an expected range, this is why you will almost always see a ± symbol beside a torque hinge. Even if you do not see this symbol, there is variability. This is not unique to any manufacturer but is an inevitable byproduct of the process of creating torque hinges. This is why it is important to accurately calculate the use case in order to ensure that the hinge will work properly, even with variation.

Choosing a product that is below but close to the lower limit is important. If it is above the lower limit, the hinge is not guaranteed to provide free stop (undercompensating). If is too far below the lower limit, the lid/flap/panel/ or other movable component will become very rigid and difficult to move.

HG-TS15 Torque Hinge, part of HG-TS Torque Hinge Series
HG-TS15 Torque Hinge

The HG-TS15 torque hinge on the right, (part of the HG-TS model), has a kgf (kilogram force) of 15.3 cm/per unit. It also has a potential +40% and a potential -20% force beside its torque measure. This means that the torque can be as much as 21.42 kgf/cm pc or as low as 12.24 kgf/cm.

Additional functions

Not only are there different amounts of torque, sizes and shapes, there are also different functions. Below are a few of the types of functions for different units at Sugatsune.

One way torque hinges

These hinges have friction which only activates in one direction. This feature makes opening and lifting easy while still retaining its free-stop functionality.

Example of one way torque functionality
Adjustable torque hinge functionality
Adjustable Torque Hinges

Adjustable torque hinges contain the functionality to adjust the level of torque exerted in the hinge. This can be very useful when fine tuning torque hinges to make operational feeling as ideal as possible.

Detent Torque Hinge

Detent torque hinges are able to hold torque hinges completely closed. This protects against "spring back", an inherent property of torque hinges without a detent. "Spring back" is a phenomenon that occurs due to the presence of torque. This causes hinges to be unable to close completely.

Detent torque hinge functionality

Next Steps

Torque calculation explanation
Find out how to measure torque

Torque calculator Sasuga-kun
Torque calculator, product selector and simulator "Sasuga-Kun"

Torque Hinge Selection
Sugatsune's selection of torque hinges

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